Many manufacturing processes and steps are carried out in high vacuum environments at wide ranges of temperatures and internal conditions. Ionic sputtering processes and optical coating processes are examples of high vacuum processing of materials. Typically, materials or specimens to be processed are contained within trays, carousels, cassettes or other carriers within the high vacuum chamber. During process steps within a high vacuum environment, often it is necessary to manipulate a specimen or its carrier in order to move the specimen from one process step to another, or to move the specimen into a viewing position, or to carry out other useful tasks within the high vacuum environment.
Heretofore, devices have been proposed for providing relatively simple mechanical movements to be transmitted through a wall of a vacuum vessel. These movement-providing, sample manipulating devices, referred to in the art as "wobble sticks", are typically adapted for handling specimens, samples or the like; or, for operating mechanisms within the vacuum chamber, such as shutters, adjustment probes, and variable orifices. Wobble sticks have typically been gimble mounted rods which pass through a mounting flange affixed in sealing arrangement to the wall of the vessel. Typically, such rods have permitted some limited relative axial movement and some limited angular displacement. Usually, axial movement has been limited to about twelve centimeters or less, and angular movement has been limited to about plus or minus twenty degrees from perpendicular to the vessel wall. Some limited range of rotation has also been provided in prior art wobble sticks. Unrestricted, multi-revolution rotation has not been available heretofore.
One source of prior art wobble sticks is Vacuum Generators Limited, Menzies Road, Hastings, East Sussex TN341YQ, England. Their models WS2, WS50, WS120, WS75PG, and WS50FG are examples of the state of the prior art and are described in a Vacuum Generators Limited brochure, number 04 010 979 (revised 5/84), reference to which is made for further particulars.
As described in the referenced brochure, there are three distinct types of prior art wobble sticks. One conventional type is a simple, single bellows and plunger mechanism without a sample holder, such as the model WS2. A universal type is provided with a double bellows and plunger arrangement so as to be used with a particular design of holder to lift and carry a specimen within the vacuum system, such as the models WS50 and WS120. A third, or double acting, type incorporates a third bellows mechanism and a co-axial actuator. This prior design enabled the specimen to be gripped by jaws at the interior end of the wobble stick which were releasable from the ambient via coaxial manual actuation.
While some limited rotational capability was provided by the prior art wobble sticks, the prior art units were not freely rotatable from the ambient over an unlimited range of rotational movement. One reason for this limitation has been the necessity of bellows which have been required in order to effectuate a positive high vacuum seal between the wobble stick and the ambient. Another limitation has been the relatively limited range of axial (longitudinal) displacement which limited he effective range of usefulness of the wobble stick.